Many different types of containers are known in the prior art which enable the separation of two components of a mixture until use of the mixture is required. In containers where two or more products are supplied pre-mixed, the potency of the mixture may reduce rapidly with time. For example, mixtures such as medicines and antidotes have a limited shelf life after the active ingredients are mixed.
Some of the prior art containers have a membrane fitted into the interior of a lid of the container, the membrane made of tinfoil or thin plastic for example, which can be perforated by application of external pressure to an upper surface of the lid in order to actuate movement of a depressible tab or knife edge located in the lid. These containers are generally of complex construction which can make them costly to manufacture.
Generally in order to safely access the contents of the known prior art vessels, a multiple-step opening procedure must be followed. In each of U.S. Pat. No. 6,138,821 (Hsu) and DE19950884 (Wella AG), a prior art container is shown in which the lid of the container has a compartment which is opened by moving the lid so that a fixed projection opens the compartment therein. In the case of U.S. Pat. No. 6,138,821 (Hsu), once the compartment in the lid has been opened, and the lid is removed, the sharp projection fitted to the bottle throat needs to be removed by hand so that the contents can then be consumed without any risk of injury to the lips of a user. This introduces the possibility of injury to the fingers of a user, or contamination of the contents of the vessel by touching the throat region with dirty fingers. In DE19950884 (Wella AG), the actuation of the compartment opening mechanism by rotation of the cap downward in one direction causes the sharp projection to fall into the bottle itself and presents an even greater hazard to users if oral consumption by humans from such a bottle occurs. To access the bottle mouth for rapid pouring out of the contents, the cap then needs to be rotated in a reverse direction. Such a device is unsuitable for dispensing a tablet from the cap, and small fragments of foil may dislodge and fall into the bottle.